PROJECT SUMMARY/ABSTRACT Adolescents and young adults (AYA) with type 1 diabetes (T1D) are especially at risk for missed diabetes visits and suboptimal self-care behaviors, as evidenced by their poor glycemic control with very high A1c levels. Further, diabetes distress is common in AYA with T1D and contributes to their suboptimal self-care behaviors and outcomes. The American Diabetes Association (ADA) recommends routine screening for diabetes distress and, when identified, referral for diabetes education or mental health treatment. Persons experiencing diabetes distress are at increased risk for missed medical appointments and deficient diabetes self-management. This is concerning because, without intervention, diabetes distress does not remit and either remains stable or intensifies over time. Further, AYAs may not adequately access or use advanced diabetes technologies due to perceptions of possible increases in self-care burden and diabetes distress when, in fact, such technologies could aid in their efforts to enhance self-care and improve glycemic control. Thus, there is an urgent need to develop practical and widely accessible interventions that target diabetes distress, self-care, and glycemic control and include face-to-face and remote visits to facilitate uptake. In the proposed 2-year randomized clinical trial, we will implement and assess the impact of a behavioral/psychoeducational intervention to reduce diabetes distress, increase acceptance of self-care behaviors (with or without diabetes technologies), and improve glycemic outcomes in AYAs with T1D. As a group, AYAs with T1D represent the subpopulation of all persons with T1D across the lifespan that has the poorest glycemic control, reaching a peak mean A1c value >9% at age ~19. AYAs with T1D often experience diabetes distress, which is linked to poor glycemic control, making them ideal participants for the proposed study. We will recruit 180 AYAs (ages 14-25) with T1D duration of at least 1 year and suboptimal diabetes control (A1c 8-13%). Participants will be randomly assigned to a usual care control condition or the intervention group. The intervention group will participate in monthly intervention sessions with a study interventionist during the first year. Of the monthly sessions, 4 will focus on improving glycemic outcomes in face-to-face sessions and 8 will focus on reducing diabetes distress in remote, virtual sessions to limit study burden (and in recognition of paradigm changes in care delivery during SARS- CoV-2 pandemic). To ensure adequate recruitment and retention, the control group will receive a delayed intervention and participate in the monthly sessions during the second year of the study. Both groups will use continuous glucose monitoring (CGM) for 14 days every 3 months and complete surveys every 6 months. A1c will also be measured centrally every 6 months. We will compare the two groups on the primary glycemic outcome of percent time-in-range (TIR) of 70-180 mg/dL assessed by CGM and on the secondary outcomes of diabetes distress and A1c from baseline to 1 year. We hypothesize that the intervention group will have an improvement in percent TIR, diabetes distress, and A1c compared with the usual care control group.